The UK law says you cannot listen into transmissions that you don't have permission for.

Obviously, we have permission to recieve and transmit on the ATC frequencies so no problem.

And United is registered in the US, so in large part, US (and not British) law applies to the plane and activities that happen aboard.

Apologies for going off on a tangent, but would that also determine the drinking age onboard?

I believe that it would (I was 21 when I flew internationally on UAL, plus I didn't order anything at the time), because the smoking regulation is applied across all internationally flying US carriers, and that is applicable law. Once again, call the airline for confirmation on that; IANAL.

The drinking age being based on the country of origin seems to be the case though a lot of airlines and aircrew are more concerned with their bar sales than any rules so enforcement can vary (a US registered aircraft operating a service for a non-US airline would raise some interesting legal issues I suspect - I bet a good lawyer could have a field day with code sharing flights!). Whilst on the ground in any country the rules of that country apply. If you are ever transiting a 'dry' country like Saudi Arabia, even if you are not leaving the plane, make sure you hide all alcohol away or it can (and will!) be confiscated!

Back to the channel 9 discussion, the age of the aircraft per se is not an issue - see my previous post concerning DC-8s - but very likely some specific aircraft types' sound systems were not connected for this function and at other times may just not have worked - having that facility working would be a very low priority for the maintenance staff.

The UK law says you cannot listen into transmissions that you don't have permission for.

Obviously, we have permission to recieve and transmit on the ATC frequencies so no problem.

And United is registered in the US, so in large part, US (and not British) law applies to the plane and activities that happen aboard.

Actually youre wrong.....ICAO law states that the pilot in command of an aircraft will follow laws applying to the following:

1. The states (airspace) the aircraft is flying in 2. Country the aircraft is registered

In that order......hence even the it is an Amercian registered aircraft, when flying in UK airspace UK law will have priority over US law.

Same with licencing....If a pilot with an FAA PPL flys in the UK he/she must abide by UK law.

But as stated before....these laws apply to what the "aircraft" can do. So any communications inside can be listened to becasue its kept inside the aircraft. Same as alcohol.....in UK soverienty you can drink at the age of 18 but onboard a US registered aircraft then US law would still apply.